Various medical procedures utilize resilient tubes to carry fluids, and on-off control of the flow of fluids through the tubes is obtained with a variety of devices, including stopcocks and clamps. For example, the balloon of a balloon catheter is commonly inflated with a syringe which forces inflation air through a resilient tube. When the balloon has been properly inflated, the tube is occluded with a clamp. Following use of the balloon to position the distal end of the catheter, the clamp is opened and the syringe is removed to deflate the balloon. In medical procedures such as this, it is important that the clamp be readily accessible to, and easily operable by, the physician.
Hickey U.S. Pat. No. 2,722,932 shows a tubing occlusion clamp which forms an open loop in the releasing or unclamped position. The open loop is subject to being caught on external members and permanently distorted. The distortion may prevent the clamp from completely pinching off the tube, or conversely, may cause the tube to be pinched so tightly that it is cut by the clamp. A similar prior art clamp which forms a closed loop in the unclamped position, but is not locked in the closed loop, is subject to the same problems.